package Demo;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {
    private ServerSocket serverSocket = null;
    public TcpEchoServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }

    public void start() throws IOException {
        System.out.println("服务器启动!");
        ExecutorService service = Executors.newCachedThreadPool();
        while (true) {
            Socket clientSocket = serverSocket.accept();
            service.submit( () -> {
                try {
                    processSocket(clientSocket);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            });
        }
    }

    private void processSocket(Socket clientSocket) throws IOException {
        System.out.printf("[%s : %d] 客户端上线\n", clientSocket.getInetAddress()
               , clientSocket.getPort());
        try (InputStream inputStream = clientSocket.getInputStream();
             OutputStream outputStream = clientSocket.getOutputStream()) {
            while (true) {
                Scanner scanner = new Scanner(inputStream);
                if (!scanner.hasNext()) {
                    System.out.println("客户端下线!");
                    break;
                }
                String request = scanner.nextLine();
                String response = process(request);
                PrintWriter printWriter = new PrintWriter(outputStream);
                printWriter.println(response);
                printWriter.flush();
                System.out.printf("[%s : %d] req: %s, res: %s\n", clientSocket.getInetAddress()
                       , clientSocket.getPort(), request, response);
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            clientSocket.close();
        }
    }

    public String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server = new TcpEchoServer(8080);
        server.start();
    }
}
